How do I rid of thoughts and images I don’t want

So I’m 19/m and I’m an EMT/FF and I’ve seen so many horrible things, and I always keep seeing the faces of the people I’ve seen who watch their close family die. It’s so horrible, the pure grief, not at all like movies because I know it’s real and I’m there. They look at me to save their loved ones and sometimes the world decides it’s their time. This one guy kept coming back and coding again, his wife was there, pure happiness and then instant grief again. That’s just one example, I see peoples faces that I’ve treated, people in severe pain, gosh their faces stick with you, their nerves on fire and looking to me and the medic for help. I hate talking to people in person because I’m ashamed that I’m the way I am, I feel so weak at the station after a terrible call and the other guys are joking with each other over lunch. I feel like I’m the only one that is devastated by these calls. I’m so horribly upset about it. It doesn’t help that I have so many mental conditions, to name a few, Depression, OCD, anxiety, PTSD I’d assume, one psychotic break years ago. So I know I already have mental instability. I just need these images to go away. I can’t stand it, I feel like it’s my fault, like I could’ve performed CPR better, or did better on everything. And I am not quitting my job ever. This career is locked in for me, I wanna do everything this body’s capable of with helping people, so that’s not an option. Sorry for the long post